Railway-track brake.



'J. B. ATWOOD. RAILWAY TRACK BRAKE.

APPLICATION TILED DI10.'2, 1907. 952,493. Patented Mar.22, 1910.

2 SHEETS-SHEET 1 HEM ANDREW B, GRAHAM 20 Puma L nnGRAvHEns, wAsmNawN DkciQQj EEY- EIEK AE 1,538 l H T BEST AVAILABLE cow J, B. ATWOOD. RAILWAYTRACK BRAKE.

Arnicgnon 21mm 1330.2, 1907. Patented Mar. 229 1910.

H 2 SHEET$-$HEET 2.

1 UN STATES PATENT OFFICE.

JOI-I N BAIRD ATWOO D, OF ALLEGHENY, PENNSYLVANIA.

RAILWAY-TRACK BRAKE.

To all whom it may concern:

Be it known that I, JOHN BAIRD A'rwoon, a citizen of the. United States,residing at Allegheny, in the State of Pennsylvania,

have invented a certain new and useful Railway-Track Brake, of which thefollowing is a specification. Y

My invention relates especially to means for controlling the movementsof cars on tracks by stationary brakes, and to brakes g for such purposeoperated by electric means.

Its primary objects are to provide eflicient means for stopp ngor'holding cars on the grades of switch yards, etc., to provide anautomatic brake and a brake of regulable power; to design eflicientelectro-magnets for such uses, and otherwise to improve and perfectstationary car handling brakes, as hereinafter more fully set forth.

I have illustrated the invention in several forms 1n the accompanyingdrawings,

where1n Figure 1 is a side elevation showing a sin le air of ma neticbrakes en 'a 'in all 5 33 b i) b the wheels of a: car at once. Fig. 2 isa cross section of the brake bars, and front elevation ofa car truck andwheels.

7 Fig.8 is a partial plan of a single bar brake, mounted to slide. Figs.a and 5 show respectively in side elevation and cross section a modifiedform of brakes in pairs, to be operated by the car wheel itself. Fig. 6shows a further modification using a double point magnet,

and Fig. 7 shows the use of a four-pole magnet with the wheel forming anarmature. Figs. 8 and 9 are respectively a plan and a side elevation ofsome switch yard tracks arranged for convenient use of my invention.

Fig. 10 is a further modification.

The great danger to both life and propcrty, in hand-operated brakes forswitching cars are well recognized; but so far all proposedstationarytrack brakes operated from a distance have not been eflicientfor handling heavy trains in switch yards. Such devices cannot be usedunless thoroughly rel1- able; and very great power, easily controllable,is essential to success.

down inclined switches.

is indicated in Figs. 8 and 9, where several branch tracks 12, 12, 12",are given a decided slope as shown in Fig. 9, and on each Specificationof Letters Patent.

Application filed December 2, 1907.

Serial No. 404,838.

switch, at as many places as desired are placed stationary brakes 13,13, 13", all operated preferably by electric wires 14E from a centralobservation tower T; and regulated by electric switches t.

In Figs. 1, 2 and 3 the tracks 15 are constructed as usual, andalongside them, on one or both sides,I place long magnet bars 16,preferably made of soft iron H beams and either supported to slide onthe cross ties as in Fig. 3, or better, mounted on pivoted arms 17 asshown in Fig. 2. These bars have a limited motion to and from the rail15 and are placed so as to engage the edge of the iron car wheels 18 alittle above the rail top or the dead point of the wheel. They are woundwith wire in any convenient manner as in the lengthwise fashion shown,and are energized by means located preferably in the central tower T,where the current strength is regulated and applied by a switch board t.When the operator wants a car stopped at the point where one or-more ofthese brakes is 10-- cated he throws on the current to energize themagnet 16, which by its attraction clings strongly to the car wheels andstops their rotation not only by friction but also by the magnetic dragand by the cutting of the lines of force by the moving wheel acting asan armature. There the single track brakes are used only on the insideof the track as at Fig. 3, the bars 16 are preferably connected bytoggle links 19 pivoted on the cross tie and slanting back against thedirection of the cars motion, so that the friction and tendency to creepforward thrusts the bars the more tightly against the wheels.

A more ei'licient form of the brake is shown in Figs. 4. and 5, whereelectro-mag nets .20 are mounted on trunnions 21 carried in brackets 22alongside the rail 15 so as to engage the wheel 17 by both poles N and Sat once. The iron is formed in a horse-shoe shape and the coil 23 iswound as shown and connected at one end directly to the line from thesource of current and at the other end to a spring 24: which is normallyinsulated. This spring is arranged so that soon as both poles is and Sstand opposite the wheel the latter engages it and thus makes electricconnection with the rail through which the circuit to the source iscompleted. The coil thus becomes energized when the wheel engages bothpoles of the magnet and remains energized un- Patented Mar. 22, 1910.

til the wheel leaves both the poles,the spring depressing as shown. Themagnets are preferably placed in close succession so that each wheelwill be continually passing through a field and acting as an armaturemoving across the poles. It will be understood that while the mechanicalfriction due to the pressure of poles N, S, on the wheel flange willhave a powerful retarding effect, a still stronger retardation isefi'eoted by the moving of the wheel across the poles acting as anarmature. This is due in part to the resistance to cutting the lines offorce which run through the wheel and in part to the magnetic drag whichseems to result probably from small iron particles having their polarityaltered as they are disturbed by the friction. I do not of course limitmyself to any theory of action; but the effectof the device described isto retard both the rotational and the linear motion of the wheels withgreat power and the car can be either stopped or retarded at any pointdesired, by proper manipulation of the current. It is to be noted thatno current is being used at any time except in the coils employed to acton the wheels. lVhen the car is stopped the magnets still hold it inplace, and it is released by shutting off the current, as will beobvious.

In Fig. 6 is shown a form of magnet in which the wheel directly closesboth the current and the magnetic circuits and forms a direct armatureto the magnets. Thus, along the track 15 I place any desired number ofshow magnets 25 which have wearing shoes 26, 27 forming the brakes andpoles. On the arms are wound coils 28, 29 in series so that 26 becomes anorth and 27 a south pole, for example. The circuit is completed by therail 15 when both the rail and pole 26 are in contact with the wheel.The magnet loop may be thin enough under the rail to bend if desired andit is insulated from the rail. The blocks 26, 27 normally stand inposition to lightly engage the wheel, but the latter may easily crowd inbetween them as they have sloping faces.

Evidently, in operation each wheel makes the contact to energize eachelectromagnet as it comes to it and while in contact forms the armaturebetween the poles. The shifting of position of the lines of force in it,the mechanical friction, the magnetic drag, and the direct attraction asit attempts to shiftposition or directly draw upward out of the magnetpoles,all contribute to produce a very powerful retarding effect, whichcan be regulated at the central station as desired.

It is not essentialto my invention, in its broader aspects, that themoving wheelshould be the armature, for it may sometimes be advisable tomake the wheels themselves the poles of an electro-magnet and use astationary armature bar, as illustrated in Fig. 10. The coil therein 30is carried on the car axle and energized by means carried in the car;the iron bars 31 are the armatures, of which any number may be placedalong the track.

A further modification of my invention is shown in Fig. 7, where theiron plate 32 and the four posts 33 carrying pole blocks 34, form acompound magnet with two pairs of poles as indicated. The wheel cominginto contact with the second pair completes the circuit and the fourcoils 35 are energized. The wheel then forms at once four armatures aswill be evident and any mo tion is resisted both by the lines of forcebeing cut and by the direct attraction.

Having thus described my invention and illustrated its use, what Iclaimas new and desire to secure by Letters Patent, is the following:

l. A track brake for cars comprising an electro-magnet and an armature,the two 00- operating to prevent turning the wheels, and the car wheelsforming one of the said .cooperating parts, substantially as described.

2. An electric track brake for cars in which the car wheel forms thearmature of an electro-magnet.

3. A track brake comprising an electromagnet mounted in the track andadapted to engage a moving car wheel.

4. An electro-magnetic track brake operated by the wheels of the car tobe retarded.

5. The combination with a car wheel and a rail of an electro-magnetmounted to engage the wheel and having a circuit for its coils completedby the engagement of the wheel with the track and magnet.

6. The combination of an inclined track, a series of electro-magnetsplaced to engage car wheels on the track when energized and meansincluding the car wheels to close the energizing circuit.

7. A track brake comprising a four-pole magnet placed to have all themagnetic circuits completed by a wheel on the track.

8. A railway track brake comprising an electro-magnet anchored under therail and adapted to engage a wheel thereon so that the latter forms anarmature.

In testimony whereof, I have hereunder signed my name in the presence ofthe two subscribed witnesses.

, JOHN BAIRD ATWOOD.

Witnesses:

F. W. H. CLAY,

FRED STAUB.

